20 PLATE X. [Assembly 



Fossils of the Oriskany sandstone (p. 59). 



1. Spirifer arenosa. 



2. Renssel^ria ovoides. 



3. Same, profile view. 



4. Orthis hipparionyx, internal cast of upper valve. 



5. Spirifer arenosa, do do of lower valve. 



6. Eatonia peculiaris, side. 



7. Same, hinge. 



8. Same, front. 



